Lamps or lamp strings have been widely used to decorate trees, buildings and so on for celebrations or festivals. The lamps or lamp strings are sometimes used for advertisement purpose, for example to highlight an advertisement board.
Conventionally, the lamps are connected in series or parallel with electrical wires and the lamps and wires are fixed by means of, for example, threads to a tree or a building. The lamps are lit in a pre-determined sequence to provide the decoration or advertisement purpose and no visual decoration of the lamps themselves is provided. It is therefore desirable to provide a lamp having visual decoration effect and also a lamp string formed with such decorative lamps.